As a singer to playback music, does the quality of the playback affect intonation?

Question

I am an amateur sound engineer. I often have choirs and singers that practice, and sometimes perform, to playback music. Often I use MP3 files with reasonable compression, as these are sometimes provided with performance licences of various musicals.

It's obvious that a very bad quality (read strong compression) sounds awful, but would a slight compression, which is not distracting by itself, (like e.g. from Spotify), make a difference for a solo or choir singer? The singers I work with mostly are by no means professionals, but I guess this does not matter for this question.

Specifically, I wonder whether the quality (by this I mean compression) of playback music does affect the ability of a singer to intonate correctly.

Answer 1

No, mp3 compression doesn't affect pitch of the recording, and shouldn't mater for the performer. Of course very strong compression which introduces audible artifacts might cause some discomfort, but even then I think one can sing along fine. I would be more concerned about quality of the audio that the audience hears, and that's certainly a reason to look for good quality recordings.

At high bitrates or high quality settings, if the recording sounds good, it's good. For reference, spotify "high" quality setting corresponds to 160 kb/s which is already very decent, and "very high" to 320 kb/s, which is unnoticeable to most people, especially in live music setting. https://support.spotify.com/us/article/audio-quality/

An effect that may affect pitch is the sample rate. Presently two common standards are 48 kHz and 44.1 kHz. Most modern software and hardware will recognize and convert the sample rate seamlessly, but a failure to do so may results in the recording being played about 1.5 semitone too high or too low. This may go unnoticed until the singers find they can't hit the top or the bottom note.

Answer 2

Extremely doubtful. During the process, the pitch may change very slightly, changing the 'key', but not so much as even a semitone, so that wouldn't affect intonation, only 'key', and would be hardly noticeable to anyone without absolute pitch.

Since everything in the recording will be affected to the same degree, the intonation would be affected in the same way, so it would stay constant and faithful to the original. Compression ignores the more periferal pitches, but that would not change any intonation. More influential will be the quality of amplification and speakers used to reproduce the new recording - but still no change.